1. Field of the Invention
The present invention relates to a step and gap measuring instrument, more specifically to a step and gap measuring instrument that is provided with a spindle disposed on a case body movably in the axial direction of the spindle and a contact point disposed at one end of the spindle, and measures the height of a step and/or the width of a gap by making the contact point abut a workpiece.
2. Description of Related Art
Conventionally, a dial gage or the like has been used for the measurement of a step and a caliper or the like for the measurement of a gap. As a consequence, there has been such problems that, when it is attempted to measure both a step and a gap of a workpiece, at least two kinds of measuring instruments have been required, for example, a dial gage or the like firstly to measure a step and a caliper or the like secondly to measure a gap, and that has involved an immense amount of time and effort.
As a means of solving the problem, an inside measuring instrument is proposed in Japanese Unexamined Patent Publication No. Hei7-113603. The inside measuring instrument is configured so as to be equipped with: a case body; a spindle disposed on the case body movably in the axial direction thereof; a conical contact point that is disposed at the tip of the spindle and has a conical side face abutting a workpiece; a displacement detector that detects the displacement of the spindle; a computation controller that computes the gap between the measuring portions of the workpiece on the basis of the displacement of the spindle detected by the displacement detector and a constant based on the conical shape of the contact point and displays the computation results on a digital display; and a reference piece that is attached to the case body and provides a reference end face.
Such an inside measuring instrument makes it possible to measure a gap of a workpiece by inserting a contact point into the gap. Firstly, the contact point is inserted into a gap until the reference end face of a reference piece abuts the reference flat face of a workpiece. By so doing, the spindle moves in such a direction that the spindle is squeezed in the case body and the displacement is detected by the displacement detector. The computation controller computes the gap of the workpiece on the basis of the detected displacement and a constant based on the conical shape of the contact point and displays the computation result on the digital display, and consequently an operator can know the gap by reading the result on the digital display.
Further, since the inside measuring instrument can be also used as a conventional dial gage, it is possible to measure a step as well by using it.
That is, by using the inside measuring instrument, both a step and a gap can be measured with a single instrument.
With an inside measuring instrument disclosed in the aforementioned patent document however, a gap cannot be measured in the case of a shape formed in such a way as integrating a step and a gap inseparably as shown in FIG. 12. That is, since the shape of the contact point of the inside measuring instrument is conical, it is impossible to insert the conical contact point perpendicularly to the gap in such a case as shown in FIG. 12, and consequently the gap cannot be measured.